Trtjss-bridge



UNITED sfrarss PATENT oFFIcE.

HORACE CHILDS, OF HENNIKER, NEVIT HAMPSHIRE.

TRUSS-BRID GE.

Specification of Letters Patent 1\T o. 4,693, dated August 12, 1846.

To all whom t may concern.'

Be it known that I, HORACE CHILDS, of Henniker, in the county ofMerrimack and Stateof New Hampshire, have invented a new and usefulImprovement in Bridges, and thatl thegfollowing is a full, clear, andexact description of the principle or character thereof whichdistinguishes it from all other things before known and of the man nerof making, constructing, and using the same, reference being had to theaccompanying drawings, making part of this specification, in which-Figure 1 is a longitudinal vert-ical elevation of the truss frame of abridge on my improved plan; and Fig. 2, a vertical cross section takenat the line (X X) of Fig. 1.

The same letters indicate like parts in all the figures.

In the truss frames of bridges diagonal suspension rods have long sincebeen used, provided with screw nuts below the lower and above the upperstring pieces, by means of which the truss may be cambered, but for noother purpose, and the wooden braces extending diagonally from post topost and between the upper and lower stringers and rest-ing againstblocks, have, and can only be used as thrust braces. The defects ofthese modes of construction are obvious if two thrust and counterdiagonal braces are used the suspension rods for cambering are requiredin addition, thereby greatly in` creasing the weight of the bridge,-andif thrust braces only are used then too much strain rests on the posts,either of which is a serious defect. Another defect is that the diagonalbraces which bear against blocks above and below have nothing to bindthe stringers and posts together except the keys and bolts passinghorizontally through them.

The object of my improvements is to avoid these defects without. addingto the weight and cost of the struct-ure, and this end I attain byemploying the suspension and cam` bering rods in such manner as toanswer in addition to these the purpose of diagonal counter braces, byusing additional nuts above the lower and below the upper string pieces,which rods passing diagonally through the stringers where they areunited with the posts bind and hold them together. And combining withthe diagonal thrust braces short' screw bolts which pass diagonallythrough the stringers where they'are united with the post, attop andbottom to bind them together, in the same manner but in the reversedirection o f the suspension rods. j

In the accompanying drawings (a) and (a) represent the upper and lowerstring pieces, (b) the posts, and (c) the diagonal thrust braces whichare made double; and have between them at the upper and Ylower end ascrew bolt (d, CZ) secured by a metal pin (e, e) passing through thebrace and an eye in the end of the bolts. These bolts extend beyond theends of the braces sufficiently to pass diagonally through the junctionof the stringere and posts and then receive nuts (f f) which bearagainst blocks (g, g) placed in the angles formed by the junction of thepost and stringers, and similar to the shoe pieces (k, L) employed toreceive the thrusts of the braces, in the usual manner. The suspensionrods (i, i), two to each section, are inclined the reverse of the thrustbraces and cross them, and pass through the junctions of the posts withthe stringers in the samey manner as the bolts (CZ, d) but in additionto the outside nuts (Z, Z) above the upper and below the lowerstringers, there are two additional nuts (m, m) that bear against shoepieces or blocks (n, n) below the upper and above the lower stringers,so that by binding the stringers and posts at top and bottom by means ofthese nuts the rods answer the double purpose of suspension rods andcounter braces, at the same time that they, in connection wit-h thebolts (d, (l) at the ends of the thrust braces, bind and secure togetherthe posts and stringers.

I generally employ in each truss two rods to each section one on eachside of the thrust braces', but more or less may -be used wit-houtchanging the principle of my invention. What I claim therefore as myinvention and desire to secure by Letters Patent isl. The employment ofthe additional nuts upon the suspension rods under the upper and abovethe lower stringers, substantially as herein described, whereby thesuspension rods answer .the additional purpose of as described, wherebythe braces, posts, and

counter braces,'as described. stringers are bound together as herein de-2. And I valso claim the employment of scribed. the screw bolts combinedWith theV thrust HORACE CHILDS. 5 braces, and projecting beyond themsuli- Vitnesses:

ciently to pass through the stringers Where ROB. B. EATON,

they are united with the posts substantially PAGE EATON, Jr.

